title: A method to develop an in vitro osteoporosis model of porcine vertebrae: histological and biomechanical study.
abstract: OBJECTIVE
  The porcine spine is widely used as an alternative to the human spine for both in vivo and in vitro spinal biomechanical studies because of the limited availability and high cost of human specimens. The aim of this study was to develop a reproducible in vitro osteoporotic vertebral model for spinal implant investigations.
  
  
  METHODS
  Four mature domestic porcine lumbar spines (L1-5) were obtained. An in vitro decalcification method was used to decrease the mineral content of the porcine vertebrae, with Ca-chelating agents (0.5 M EDTA solution, pH 7.4) that altered the bone mineral density (BMD). Lumbar-spine area BMD was evaluated using dual-energy x-ray absorptiometry; spine volumetric BMD and spine geometry were assessed by central quantitative CT scanning to monitor the time it took the decalcification process to induce the WHO-defined standard of osteoporosis. Micro-computed topography provided information on the 3D microarchitecture of the lumbar vertebrae before and after decalcification with EDTA. Hematoxylin and eosin staining of lumbar vertebrae was performed. Both the control (5 specimens) and osteoporotic vertebrae (5 specimens) were biomechanically tested to measure compressive strength.
  
  
  RESULTS
  The differences in area BMD measurements before and after the demineralizing processes were statistically significant (p < 0.001). The results of the compression test before and after the demineralizing processes were also statistically significant (p < 0.001).
  
  
  CONCLUSIONS
  The data imply that the acid demineralizing process may be useful for producing a vertebra that has some biomechanical properties that are consistent with osteoporosis in humans.
authors.affiliation: Department of Neurosurgery, Chang Gung University & Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors.forename: Ching-yi
authors.initials: CY
authors.lastname: Lee
authors.forename: She-Hung
authors.initials: SH
authors.lastname: Chan
authors.forename: Hung-Yi
authors.initials: HY
authors.lastname: Lai
authors.forename: Shih-Tseng
authors.initials: ST
authors.lastname: Lee
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology; D015519:Bone Density / Q000502:physiology; D019245:Compressive Strength / Q000502:physiology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D008954:Models, Biological; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D013552:Swine